issue with 97 f-150

[Camaro86SHOCKER]

The truck is a 1997 f-150 4.6 v8 2wd. It has 141,xxx miles. This week the oil pressure light came on, the gauge reads extremely low but is still registering. I immediately check the oil and add a bit just to make sure. Oil level is fine. As you drive sometimes it will just randomly come back up and the light goes off then for no reason the gauge drops and the light comes back on. The truck runs no differently and it has been like this all week. Anyone know what could cause the issue? i would think if it was a faulty oil pump then the engine would already be gone. I really don't think this is what it is, anyone else ever run into this?
Theres no rhyme or reason for when it goes up or down but it does so very irradically. Any input or knowledge with this would help as i am totally lost. No service engine soon light is one either.
It's driving me insane though i keep thinking oh crap the engines gonna kick the bucket but hell it runs fine.

-Justin

[8NO4CYL]

Oil sending unit is probably cheap, switch it out and see what happens.

[bobtsgt]

modular sending units are retarded. I have a mechanical gauge we can hook up and see what your pressure really is. The stock sender is not very accurate. As long as you don't hear any knocking sounds your alright :D sorry I missed your call too yesterday

[aperacer]

just put one on a Time Warner truck. it was F150 with about 180,000 miles. gauge would go to zero and back again. it would even turn on the "engine over temp" warning lamp.
i think it was 7 buck for the pressure sensor on or at the filter adapter and it was fixed.
the gauge would go from reading fine to nothing with no mechanical noises in the engine or anything.. and like you said no rhyme or reason to the dis-function. it took about 3 min to replace.

[Camaro86SHOCKER]

Thanks guys, that really puts my mind at ease, i'll be stopping today to pick one up. where exactly is it located? Ive heard you guys call it a few different things, what should i ask the guy at the counter for?

I feel so lost with these mod motors, i can build a smallblock/big block pushrod motor with my eyes closed but this 4.6 is always throwing me for a loop.

[aperacer]

at or near the oil filter adapter. its a one wire sensor. you can get to it from under the truck. oil pressure switch would be the correct name. good luck.

[Camaro86SHOCKER]

Ok i bought the part and researched it, is all my oil gonna drain out when i remove this? Should i change the oil at the same time as this? I just wanna be prepared cause my time frame to do this between my 7-day a week job is pretty small lol.
Thanks again for all the help.

[aperacer]

no oil needed. i had a little dribble when i did the one i had. shop rag or small drain pan just to catch it. its not under pressure when the engine is running so it will be just a dribble